The overall aim of this proposal is to continue the development of a large HMO, Group Health Cooperative of Puget Sound (GHC), as a shared population laboratory for the conduct of cancer control research. The specific aims outline a series of enhancements to the GHC "Mini-population laboratory" for the conduct of cancer control research. The specific aims outline a series of enhancements to the GHC "Mini-population laboratory" so as to better support those specific proposals in the Cancer Prevention Research Unit (CPRU) program project which require access to GHC enrollees, providers, data, or research support. The specific aims are: 1. To further develop analytic data files from existing GHC computer systems to support cancer control research. This will include enhancements to: the system supporting the Breast Cancer Screening Program; the computerized Tumor Registry; the new Pathology System (to develop registries of pre-cancerous lesions such as colonic polyps or cervical dysplasias); and the Laboratory System (to identify recipients of Hemoccult testing). 2. To provide computer programming and biostatistical expertise in the use of GHC computerized databases to support specific projects. 3. To provide research, administrative, and logistical support for program project activities including assistance with subject identification and sampling, recruitment of patients and providers, access to medical records and other data, and access to GHC computer databases. 4. To coordinate the independent cancer control research program of GHC's Center for Health Studies with the individual projects and overall program of the CPRU program Project, including the sharing of data.